Materials and Methods: A randomized controlled of trial carried out in a university hospital from April to August 2015. The Laminaria group patients received a single intracervical Laminaria tent (2-3 mm in diameter) 12 hours prior to the hysteroscopic procedure. The Evening Primrose Oil group of patients received 6 intravaginal Evening Primrose Oil capsules inserted into a posterior fornix 6 hours prior to the procedure followed by another 4 capsules inserted 1 hour prior to the procedure.

Results: both Laminaria and Evening Primrose Oil were effective in dilating the cervix, but the initial cervical dilation was significantly greater for the Laminaria group. The median duration of time needed to insert the 10mm Hegar's dilator was significantly longer for the Laminaria tent group, compared to the Evening Primrose Oil group (123 seconds vs 55 seconds, P-value 0.01). The ease of cervical dilation was likewise significantly better for the Evening Primrose Oil group (26.19% vs 16.67%, P-value 0.04).

Conclusion: Both Evening Primrose Oil and Laminaria were effective in dilating the cervix. However, Evening Primrose Oil resulted in easier and faster cervical dilatation required for hysteroscopy. Evening Primrose Oil had better patient acceptability because it was more convenient and easier to use, and is less expensive, compared to Laminaria tents. Therefore, Evening Primrose Oil capsules is an easy-to-use regimen that can be recommended for patients undergoing operative hysteroscopy, to facilitate easier and faster cervical dilatation, and reduce complications associated with resectoscope entry.